The leader of South Korea's second-largest umbrella labor union received a five-year jail term Monday for last year's violent rallies in downtown Seoul.

The Seoul Central District Court found Han Sang-gyun, head of the Korean Confederation of Trade Unions, guilty of orchestrating a massive antigovernment protest in November that led to clashes with the police and a dozen other rallies between 2012 and 2015. The court also ordered the 53-year-old to pay 500,000 won ($436) in fines.

On Nov. 14, tens of thousands of demonstrators took to the streets in downtown Seoul to protest the government's decision to adopt state history textbooks and reform the labor market. The rally later turned violent as some protesters brandished metal pipes and police fired water cannons at them.

The labor union leader was convicted of all five charges slapped on him in regards to the rally, including obstruction of official duties and damage to public property.

The court said Han is responsible for inflicting injuries to 76 police officers and damaging 43 police buses, as well as illegally occupying the streets by leading protesters.

"Some of the protesters tried to pull the buses with ropes and even brandished metal pipes at police officers," the court said.

"The defendant took a role by preparing and distributing the equipment, such as ropes and ladders to climb over the bus barricades."

The court did not acknowledge Han's argument that police first unlawfully suppressed the protesters with bus barricades and water cannons. A farmer still remains in critical condition after being knocked down by a police water cannon.

While admitting that the device was inappropriately used against the farmer, the court said it does not mean the use of the water cannons itself was illegal.

The decision sparked an outcry from nearly 200 union members and supporters who filled the courtroom.

"We will continue our struggle to secure the freedom of assembly," they said during a press conference held near the courthouse after the ruling, adding they will hold massive protests starting this month.

Han's legal representative Chang Jong-oh said they will appeal the ruling. (Yonhap)